Vinyl chloride polymer stabilized with thiophosphite and polyvalent metal soap



hired States Patent VINYL CmORlDE POLYMER STABILIZED.WI'IH THIGPHOSPHITE AND, lOLhWALElhl'll-v 'ME IAL SOAP Joseph Fath, Morristown, N. J., assignor, by, mesne assignments, to Heyden Newport Chemical Corporation, a corporation of Deiaware' No Drawing. Application Augus 2. 2 14 V SEK'iHiNO-ASLZQBZ 8 Claims. o1. 260-43).

This invention embodies novel polymeric vinyl resin compositions which are more resistant to deterioration under the influence of light and heat than those' heretofore produced, as Well as to additives adapted to be incorporated in vinyl resins generally, to impart to them the characteristics referred 'to.

The invention also includes processes for the manufacture of additives useful in the'prod'uotion of such resin compositions.

A rapidly expanding industry utilizing halogen containing resins, such as polyvinyl chloride, polyvinylidene chloride or copolymers thereof with vinyl acetate, vinyl stearate, styrene, acrylonitrile and other unsaturated monomers capable of polymerization, has created an important need for stabilizers to 'r'ender'the finished articles of manufacture therefrom more usable, more versatile in application and more permanent.

A number of such stabilizers have been employed. .1

They have been used for two particular purposes. First, they are intended to prevent deterioration during processing. which involves the fusion of the commonly used thermoplastic resin powder in the presence of a plasticizer at temperatures well above 250 F. Frequently, processing time extends over the period of one hour during which the composition, in the absence'of stabilizers,

turns amber or even black, making it unfit for further use. Second, stabilizers are intended to minimize deterioration of the finished article due to prolonged eX-.

posure to sunlight and/ or heat.

The most common stabilizers for halogen containing resins are the metal soaps of a variety of fatty acids, such as, e. g., stearic, lauric, palmitic and Z-ethylhexoic acid. Among the most prominent of the metals used for more efiicient stabilization of vinyl resin composi-' tions of the character. described, but no .one heretofore has successfully supplied that need,

his not the purpose of the present invention to. elirnir nate the use of metal soap stabilizers, as heretofore em- Ploy d n e r b t rather to pmvid a tiv s. h ch.

y be used in inor m unts-in Con IiQn th ret to very materi lly accentuate and increase the performance of the stabilizers for the production of more stable end products than have heretofore been obtainable through the use of stabilizers alone.

Itmay t n' his. smn a i n. ha wh le he additives of this invention-have per s a stabilizing' 'effect ran. he-Pol m r he fi et o h l" @611 ith 'nc as ab lize .Q he h rate f ss rib d emote.

than a mere additive efiect. On the contrary, thecom bination of the two, coacting in the vinyl resin composition, appears to produce a very definite synergistic action so that the stabilizing result from both is materially greater, than the sum of the individual stabilizing actions of each. As a result of prolonged experimentation and research, I have discovered and demonstrated that polymeric halogen containing vinyl resins ofthe prior art, stabilized with metal soaps as heretofore used and which were ineffective for satisfactory commercial usage, may be. rendered highly eifective for thatpurposebythe addition to such composition of"certain'compO containing the :PS'- group. These additive compounds are characterized, by the fact that they contain alinkage of sulfur and trivalent phosphorous. Chemicals coiitaining such a linkage are represented by the formula R -s .p

Y wherein R+ is representative of the group consist. ing of thioalkyl, thi'oaryl, thio'alkaryl-and 'alkyl'thioacylate and X and Y are representative of the group consisting of thioalkyl', thioaryl, thioalkaryl, alkyl thioacylate, alkoxy, aryloxy, alkaryloxy, arylaryloxy, etc. Inthis. type of compound X and Y may be one and the, same or they may be different members of the foregoing'group of radicals. These compounds are generally/known as trithiophosphites, dithiophosphites and monothiophosphites.

The foregoing formula may also be stated as follows:

xn' RS-P in which R is selected from the group consisting of alkyl, aryl, alkaryl, and carbalkoxy alkyl, R and R are selected from the group consisting of alkyl, aryl, alkaryl, and carbalkoxy alkyl, and and Y are selected from the group consisting of sulphur and oxygen.

While it is recognized that other derivatives of trivalent phosphorus dissimilar to those described above have previously been employed in polyvinyl chloride compositions, I have demonstrated that the =P+ linkage common to the compounds of this'invention produces a stabilizing efi'ect far inexcess' of an entirely out of proportion to the effect rendered by the compounds of the prior art.

Illustrative examples of the groups hereinbefore described are as follows:

Examples of R+ are: methyl mercapto, ethyl mercapto, butyl mercapto, 2-ethyl-hexyl mercapto, tertiary dodecyl mercapto, tertiary octyl mercapto, tertiary amyl mercapto, lauryl mercapto, tetradecyl mercapto, phenyl mercapto, cresylmercapto, amyl phenyl mercapto, benzyl mercapto (the same being examples of the thioalkyl, thioaryl, thioallraryl groups), isooctyl thioglycolate,-dibutyl thiomalate, cyeloheriyl B-.,merc aptopropionate, etc. (the same being examples of alkyl thioaeylates, namely, allsyl t,ca yli ac s o aini the t iq group).

glycolate', f-butyl 'octyl B-mercapto butyl-ate, m'mtixyj vtqxyi l sthyl exgry e stearyloxy, phenylethoxy, "benzyloxy, lauryloxy, cyelo hexyloxy, terpinyloxy, cresoxy, p-tertiary amyl phenoiry,

2,824,847 a te-aged 9 5-M r-53? of'lS milsthickness were prepared by the above procedure. Sample strips ofthese films were exposed to ultra-violet light inan Atlas Electric Devices Company FDA-R Color Fadeometer and were rated visually from day to day until failure had occurred. Failure was considered as the time elapsed to obtain a color rating of as defined by the scale enumerated above. The following table is indicative of theresults thus obtained.

TABLE 11 In the preparation tof' the additive compounds of the present invention, certain novel improvements have been made which render the commercial production of these materials possible at lowercost, with better yields, faster and simpler processing, and with less elaborate equipment.

My additive compounds are prepared by the reaction of one mol of phosphorus trichloride, one mol of a mercaptan and two mols of a compound designated as XH and Y-H,'wherein H- is a hydrogen'atom and X and Y have hereinbefore been described, in an anhydrous hydrocarbon solvent. This reaction should be carried out in the presence of a hydrogen chloride acceptor in order to permit completion of reaction and the formation of the desired endproduct. Chemically, the reaction may be represented as follows:

3 mol base RSH-+ 2(X-H Y-H) PC]: X R-S-P 3 base hydrochloride If prepared in the presence of a sufiicient quantity of hydrogen chloride acceptor to remove all of the hydrogen chloride liberated from the reaction mixture, the formation of undesirable and extraneous side products is avoided and the main product is formed with an excellent yield. The reaction'is carried out in anhydrous medium in order-to prevent hydolysis of the resultant phosphorus-sulfur compound; For this reason the base hydrochloride formed cannot be washed out of the reaction despite its excellent water solubility and must be removed as the anhydrous salt by filtration.

Commouorganic bases used in'this reaction have been tertiary nitrogen containing compounds such as pyridine, dimethyl aniline, diethylaniline, etc. While the filtration of small amounts of pyridine hydrochloride, etc., from laboratory batches presents no particular difiiculty, its use in commercial manufacture is not practical because of high cost, a high order of hygroscopicity causing caking and plugging of the filter, solubility in hydrocarbons causing incomplete removal of the salt with consequent incomplete reacticn and contamination of the end product.

One novel feature incorporated in this procedure is demonstrated by the use of dimethylaniline as an acceptor for hydrogen chloride. I have found that if the reaction slurry, following the formation of dimethyl aniline hydrochloride crystals, is heated to about 80 C., the hydrochloride salt melts into a liquid insoluble in the hydrocarbon reaction medium. As such, it is permitted to settle to the bottom of the reaction vessel from whence it may either be drawn ofi or where it may be permitted to fuse into a solid cake; 1; Under the latter procedure the hydrocarbon reaction medium is conveniently decanted'and. contains no unreacted or dissolved acceptor or acceptor salt.

in either case, the hydrocarbon solveut mc dium is stripped, removing the solvent from the desired product which is free of contaminants, in practically quantitative yield, and may be used directly without. further process.- ing. The hydrochloride salt is dissolved in water, made basic with excess sodium hydroxide and the recovered base, e. g., dimethyl anil'me, extracted with the solvent previously stripped off. On azeotropicrefluxing this solvent-base solution is ready for a subsequent run. Neither base nor solvent are expended inthis way and therefore do not materially contributeto the raw materiaLcost of the phosphorus-sulfur. compound.

By this greatly simplified procedure the net hydrogen chloride acceptor becomes sodium hydroxide. which is readily expendable. Dimethyl aniline is a preferred embodiment of this aspect of thepresent invention because of its relative low cost and lackof Water, solubility on recovery, althoughother bases such as diethyl aniline, tributylamine, etc; may be'used equally well in this procedure. A great. number. of compounds of the general formula.

have been prepared in this manner generally, varying widely hydrocargon solvents, compounds represented by R--SH, Ii and Y-H and hydrogen chloride acceptors.

The following examples serve to illustrate briefly the. simplicity of this process but are not considered to ime. pose narrow'lirnitations on conditions. of preparation.

Example 1 'Into a one liter 3-neck flask equipped with'agitator, thermometer, reflux condenser with calcium chloride tube, and dropping funnel, were introduced 174 grams n-decyl mercaptan' (1 mol), 200 cc. toluene and 12.1 grams dimethyl aniline (1 mol). While agitating vigorously and cooling the flask with an ice bath, there was added dropwise over a period of three quarters of an hour, 45.8 grams phosphorus'trichloride (0.33 mol). The reaction was cooled at such rate as to maintain the temperature between 20-25" C. Atthe end of addition, agitation was continued for one hour, after which'the. precipitation of dimethyl'aniline hydrochloride was considered to be complete. The temperature was raised to C. and agitation discontinued to permit settling of fused hydrochloride salt. When separation, was complete, the upper layer was removed from the flask by suction and transferred to a still where the benzene was removed and collected by stripping in a vacuum of 50 mm. up to 119 C. The residue consisted of tri (decyl thio) phosphite,

Percent S found 17.2 Percent P found 5.8 Percent S calc. 17.45 Percent P calc. 5.64

Stark tube, until dry. To this solution may be added decyl mercaptan for a subsequent batch.

' thiophosphite'.

run; adding the aboveexpended V 7 .Example II jilntoi a l liter 3-neck flask equipped with agitator, thermometer dropping funnel and reflux condenser fitted with a calcium chloride tube, wereintroduced 82.6 grams benzyl mercaptan (0.67 mol), 200 cc. cyclohexane, 54.7

grams paratertiary amyl phenol (0.33 mol) and 149 grams diethylaniline (1.0 mol).7 Agitation was begun and when complete solution had been obtained, 45.8 'grams phosphorus trichloride (0.33 mol) were added dropwise over a period of three quarter of an hour. The

temperature was maintained at -25" C. by. external 7 (fooling; "Agitation was continuedfor one hour following;the;en d of addition. The slurry was then heated,

liguifyingat about 8 O C. Stirring was discontinued and the contents of the flaskwere permitted to cool. When the temperature of the contents had reached C., complete separation of the layers had occurred and the lower layer had fused into a solid mass. The upper eyclohexane layer was decanted, strippeddn vacuum and yielded a-residue'consisting .of paratertiary amyl phenoxy di (ben zylthio) phosphite; 300 cc. water were added to the'solid cake of hydrochloride .salt and a'solution was obtained by slight heating. .The cyclohexane previously stripped on was added to this solution, 100 grams of 50% sodium hydroxide solution were added and the cyclohexane layer'was separated and washed three times with V water;v It was returned to the'flask and refluxed with a .Dean-Stark tube to reinove water azeotropically. It was thenused for a subsequent batch by adding benzyl mer-' captan and paratertiary amylphenol'in the, above quantities. r v 'Example III.

'In'tofa51iter mercaptan (1 mol), 328 grams paratertiary amyl phenol The mixture was agitated'until uni- 3-neck flask equipped with agitator, thermometer, dropping funnel, reflux condenser. and calciumi'chloride tube, were introduced 202=grams lauryl the appended claims. I Having thus fully described theinvention, what I clainigroupconsistingof sulphur and oxygen- V The compounds hereinbefore deseribe'd are valuable V additives not only in polymeric resin compositions but also in other halogenated materials, which include'metal soap stabilizers; They'are also useful as rubber anti-oxidants; andinjlub'e'oiladditives and many other articleso'f-comj r'nerbe in needjof stabilization against deleterious eflects of light'and heat."

The foregoing "detailed tion is to be understood as' fully commensurate with as new and desire'to secure byLetters Patentfis:

.1. A resinous polymer of vinyl 'chloride,'stabilized against thedeteriorating effects of light and heat by a stabilizing amount of an admixture of at least one soap of a polyvalent metal and an additive represented 'by theformula r 7' m in which is selected from the group consisting of allyl,

aryL'alkaryl, and;carbalkoxy alkyl,jR and R. are se lected vfrornthe group-consisting of alkyl, aryl,.a.lkaryl,

and. carbalkoxy alkyl, and X and Y are selected from the,

'2. A composition accordingftoclaim 1; w

resinous polymer is a homopolymer; of vinyl chloride. 1

3 .A Composition accordingtoclaim 1, comprisinga plurality of difierent metal soap stabilizers.

f (2 mols), 600 grams benzene and 363 grams dimethylq aniliue .(3. mols).

form and then there were added 137.5 grams phosphorus trichloride (lrmol) at such a rate as to maintain the' temperature at 25 Q, with external 'water'cooling." Upon and it was then heated to 72 .C., transferred to a's'epara- V toi'y funnel and the two liquid layers were permitted to 7 separate.- 'The lower layerflwas removed while 'still liquidi by runningiit into a beaker containing 1000 cc.

water. ,The up'per'layer was stripped in vacuum, yield-.

ing a residue consisting of di amyl phenox'y mono lauryl The benzene distillate was added to thez 7 LJCOIIIPICfiOH, the slurry w as stirred for an additional hour 7 beakercontainin'g dimethylaniline hydrochloride solution, 7, z

300 grams of solution of sodium hydroxide were added with agitation followedby separation of the aque one from the *organic,' 1a er.-

V The organic layer *-was wash'edithree' times with water and dried by azeotropic refluxing. The dry solution was used 'for, .a subsequent reagents 7 1,.4; 'A compositon according to .claim 1, .wherein the f 7 composition includes ,.015.0%'jby .wei'ghtiof additive per parts of the resin;

5. A composition according to 'claimfl, whereiuthe additive is tri (decylthio'lphosphite,

6. A compo sition according to 'claim 1, whereinthe additive is mono tridecyloxy di- 2-ethylhexylthio phosphitei 7. A'co'rnposition according to claim 1, wherein the additive is di amylphenoxy mono'laurylthio phosphite.

8. A composition "according to .claim 1, wherein the additive is mono butyoxy mono lauryloxy mono laurylthio' phosphite.

V References Cite'd'in the file of. this patent UNITED STATES PATENTS description sets forth the invention' in its preferred practical forms,-but'the invenr erein the 

1. A RESSINOUS POLYMER OF VINYL CHLORIDE, STABILIZED AGAINST THE DETERIORATING EFFECTS OF LIGHT AND HEAT BY A STABILIZING AMOUNT OF AN ADMIXTURE OF AT LEAST ONE SOAP OF A POLYVALENT METAL AND AN ADDITIVE REPRESENTED BY THE FORMAULA 